Linerless labels are becoming increasingly popular due to the environmental and cost advantages associated with them. While such labels are typically provided in roll form, there are many situations in which it is desirable to provide them in pad form instead of roll form. In order to effectively and quickly construct pads it is desirable to form the linerless labels in web form, then separate each individual label from the web in a high speed manner, form stacks, and move the stacks away from the individual label forming position.
According to the present invention a method and apparatus are provided which allow the rapid and efficient formation of pads of linerless labels. Linerless labels have a first surface with an adhesive release material thereon, such as silicone. The first surfaces are typically also printed with indicia, or indicia is otherwise applied, either on top of the adhesive release material on the substrate of the label itself (typically paper although plastic and other sheet materials can also be utilized). On the second, opposite, face of the label is a pressure sensitive adhesive, which may be a permanent, removable, or releasable adhesive. The adhesive cannot permanently stick to the adhesive release material on the first face of an adjacent (in a stack) label, but rather the labels may be readily separated from each other in the stack. In this way no separate release sheets that need be disposed of are provided, resulting in significant savings in material, and landfill space.
According to a first aspect of the present invention a method of stacking linerless labels in a pad, utilizing a paddle wheel first conveyor and a second conveyor downstream from the first conveyor in a first direction, is provided. The method comprises the following steps: (a) Substantially continuously transporting the individual linerless labels one at a time in the first direction into supporting contact with a generally horizontal paddle of the first conveyor, to form a stack of at least three linerless labels with the first surface of one label engaging the second surface of an adjacent label in the stack. (b) After formation of a stack of linerless labels moving the first conveyor by rotating the paddles thereof so that the stack is elevated, and a new paddle comes into a generally horizonal position to receive linerless labels in a stack. (c) As steps (a) and (b) are practiced, ultimately rotating the paddles of the first conveyor so that a paddle supporting a stack of linerless labels moves below a transporting surface of the second conveyor, so that the second conveyor supports the stack of linerless labels. And, (d) transporting the stack of linerless labels supported by the second conveyor away from the first conveyor.
Step (d) may be practiced intermittently, in synchronous movement with the rotation of the first conveyor in step (b). There is typically also the further step of simultaneously cutting (detaching, or otherwise separating) individual labels from a web during the practice of step (a). The second conveyor movement, as well as the rotation of the paddles, is typically practiced as a result of information supplied from a sensor associated with the cut off or detaching mechanism.
According to another aspect of the present invention a linerless label stacking assembly is provided which comprises the following elements: A paddle wheel first conveyor having a rotatable central portion with a plurality of paddles extending generally radially outwardly from the central portion; the central portion along a generally horizontal axis. Means for, at spaced time intervals, rotating the first conveyor about the axis in a first direction. A second conveyor having a generally horizontal supporting surface disposed at approximately the same vertical position as the first conveyor generally horizontal axis. And, means for feeding linerless labels, each having a first adhesive release surface and a second pressure sensitive adhesive surface, to the first conveyor one at a time.
Each of the paddles of the first conveyor may have first and second curved surfaces, each surface having a first end adjacent the central portion and a second, free, end remote from the central portion. The first and second curved surfaces may have the same general direction of curvature, and the first surface is typically concave as viewed in the first direction of rotation.
The means for rotating the first conveyor may comprise a D.C. motor, or another power source such as an A.C. motor, pneumatic, hydraulic, or similar type of power source which is controlled by a controller. The controller receives sensing information which indicates when a pad of a predetermined size (typically at least three linerless labels) has been formed to effect rotation of the paddle wheel so that the next paddle comes into operative association with the feeding means.
The second conveyor may comprise a wide variety of different types of conveyors, such as belt, chain., flat horizontal surfaces guided and supported by moving elements, or a wide variety of other conventional types. One particularly suitable type is that comprising a flexible element (such as a belt or chain) having a top surface and with push arms extending outwardly from the surface for pushing pads of labels thereon away from the first conveyor.
The means for feeding linerless labels to the first conveyor may comprise roller, belt, or other conventional type conveyors and may also comprise means for separating the individual labels from a web, i.e. a cut off device. For example a rotary cut off device having first and second rotating cylinders, rotatable about generally parallel generally horizontal axes, and one having a radially extending cutting blade and the other an anvil cylinder, and having a sensor associated therewith, may be provided for simultaneously conveying a label web toward the first, paddle wheel, conveyor and simultaneously cutting it (the web) into individual labels. Alternatively the cut off device may comprise a burster for bursting the web along predetermined lines of weakness, or a wide variety of other separating devices may be utilized including scissors, guillotine, thermal, laser, and other types of cutters.
According to another aspect of the invention a paddle wheel conveyor is provided comprising the following elements: A rotatable central portion along a generally horizontal axis. A plurality of paddles extending generally radially outwardly from the central portion. Each paddle having first and second curved surfaces, each surface having a first end adjacent the cental portion and a second, free, end remote from the central portion. And, means for, at spaced time intervals, rotating the central portion about the axis in a first direction.
It is the primary object of the present invention to provide a quick and effective method, apparatus, and paddle wheel type conveyor, for forming linerless labels into pads. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.